Processing a highly viscous material such as a sugar byproduct which tends to form clumps is fairly difficult. Use of a continuous sieve-type centrifuge such as described in German patent document 3,415,519 filed 26 Apr. 1984 by Bernhard Fiedler having two stages is typically ruled out because the material forms lumps that in turn constitute offcenter masses that create so much throw as to overload the device. Such a centrifuge can only be used for relatively easy-to-handle type B sugar.
In an alternative system described in German patent document 3,622,959 filed 09 Jul. 1986 (equivalent to European patent application 252,341 published 13 Jan. 1988) also by Bernhard Fiedler the two coaxial drums are suspended from their drive motor so as to minimize offcenter vibrations. This arrangement also is not suitable for type C sugar.
Thus to separate highly viscous clump-forming suspensions such as C-sugar byproducts it is necessary to move the material manually from a single-stage centrifuge to another and to carefully load it into the downstream centrifuge. There is no known way to use a space-efficient two-stage coaxial centrifuge of the types described above.